The most common and most likely answer to this crossword clue is the 8 letter word ARGUMENT
I've seen this crossword clue in The Guardian
A
R
G
U
M
E
N
T
More clues leading to the result ARGUMENT
- Row of pawns kept by instinct beside a rook
- Rum agent stupidly causing row
- . Debate case for auditor meeting staff in corporation
- Unfriendly words are not about to stick
- Turn game off causing row
- Gunners knocked over Nutmeg’s battered case
- Controversy about cleavage
- Glue applied to a tear can be heated
- Barney‘s posh, married in white
- High German, but without British rationale
Buddy explains!

The straight part
We know that "Controversy" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case controversy = argument.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does ARGUMENT mean?
ARGUMENT noun- A fact or statement used to support a proposition; a reason.
- A verbal dispute; a quarrel.
- A process of reasoning.
- A series of propositions organized so that the final proposition is a conclusion which is intended to follow logically from the preceding propositions, which function as premises.
- The independent variable of a function.
- The phase of a complex number.
- A value, or reference to a value, passed to a function.
- A parameter at a function call; an actual parameter, as opposed to a formal parameter.
- Any of the phrases that bears a syntactic connection to the verb of a clause.
- The quantity on which another quantity in a table depends.
- The subject matter of a discourse, writing, or artistic representation; theme or topic; also, an abstract or summary, as of the contents of a book, chapter, poem.
- Matter for question; business in hand.
- (NNES) To put forward as an argument; to argue.